Square-Planar and Octahedral Gyroscope-Like Metal Complexes Consisting of Dipolar Rotators Encased in Dibridgehead Di(triaryl)phosphine Stators: Syntheses, Structures, Dynamic Properties, and Reactivity
Estrada AL, Wang L, Hess G, Hampel F, Gladysz JA (2022)
Publication Type: Journal article
Publication year: 2022
Journal
DOI: 10.1021/acs.inorgchem.2c02855
Abstract
For a variety of purposes, it is of interest to embed metals in cagelike trans-spanning di(triaryl)phosphine ligands. Toward this end, a combination of P(p-C6H4O(CH2)mCH-CH2)3 [3; m = 4 (a), 5 (b), 6 (c), and 7 (d)], [Rh(COD)(μ-Cl)]2, and CO gives square-planar trans-Rh(CO)(Cl)[P(p-C6H4O(CH2)mCH-CH2)3]2 (4a-4d). Reactions of 4b-4d with Grubbs' catalyst (first generation) and then H2 (catalyst PtO2) yield the title compounds trans-Rh(CO)(Cl)[P(p-C6H4O(CH2)nO-p-C6H4)3P] (n = 2m + 2, 6b-6d; 26-41% from 4b-4d). Two are crystallographically characterized. The Cl-Rh-CO moieties rapidly rotate on the NMR time scale at -120 °C, per the ample clearance provided by the (CH2)n segments. Steric interactions with the PC6H4O linkages are analyzed. LiCCAr displaces the chloride ligand from 6b to give RhCCAr adducts (Ar = C6H5/p-C6H4CH3, 7b/8b). The ArCC-Rh-CO rotator of 7b rapidly rotates on the NMR time scale (-70 °C), but with 8b, the longer p-CH3C6H4CC group is confined between two (CH2)12 bridges, even at 120 °C. Reactions of Re(CO)5(X) and 3c (140 °C) give octahedral mer,trans-Re(CO)3(X)[P(p-C6H4O(CH2)6CH-CH2)3]2 (X = Cl/Br), and metathesis/hydrogenation sequences yield mer,trans-Re(CO)3(X)[P(p-C6H4O(CH2)14O-p-C6H4)3P]. Reactions of 6c and 6d and excess PMe3 give the free diphosphines P(p-C6H4O(CH2)nO-p-C6H4)3P (14c and 14d, 83-75%). The addition of 14d to [Rh(CO)2(μ-Cl)]2 reconstitutes 6d (87%). Both in,in and out,out isomers of 14c and 14d are possible, but low-temperature NMR spectra show one set of signals, consistent with rapid homeomorphic isomerizations that turn the molecules inside out. Thermolyses (C6D5Br, 140 °C) effect phosphorus inversion to give in,out isomers.
Authors with CRIS profile
Involved external institutions
United States (USA) (US)How to cite
APA:
Estrada, A.L., Wang, L., Hess, G., Hampel, F., & Gladysz, J.A. (2022). Square-Planar and Octahedral Gyroscope-Like Metal Complexes Consisting of Dipolar Rotators Encased in Dibridgehead Di(triaryl)phosphine Stators: Syntheses, Structures, Dynamic Properties, and Reactivity. Inorganic Chemistry. https://doi.org/10.1021/acs.inorgchem.2c02855
MLA:
Estrada, Alexander L., et al. "Square-Planar and Octahedral Gyroscope-Like Metal Complexes Consisting of Dipolar Rotators Encased in Dibridgehead Di(triaryl)phosphine Stators: Syntheses, Structures, Dynamic Properties, and Reactivity." Inorganic Chemistry (2022).
BibTeX: Download